The average smartphone user looks at his or her phone 150 times a day - did you see that headline last week? It seemed to be everywhere after a hugely influential investment guru presented it onstage at a major tech conference.

But there was never any solid data to back it up. The numbers cited in the presentation were taken from opinions posted on a blog. And the blog post wasn't even discussing smartphones, but non-smartphones.

The tech guru who presented the much-discussed factoid last week was Mary Meeker, the legendary "Queen of the Net," as Barron's dubbed her 15 years ago. The talk she gave was her annual Internet Trends Report at the Wall Street Journal's annual D: All Things Digital conference in Rancho Palos Verdes, Los Angeles County - perhaps the most important talk in all of tech, seen by many as a "state-of-the-industry" report. As a partner at famed Silicon Valley venture capital firm Kleiner Perkins Caufield & Byers, Meeker's words can sway even the most casual investors.

The misinformation has now appeared in news stories, hundreds of tweets and on thousands of blogs. It helped Meeker make her case on one of technology's biggest stages for a whole new realm of tech, "wearables" like Google Glass. But that case was not made with facts.

There were so many problems with the slide that Meeker's team, since being questioned about it by The Chronicle, has changed its headline and its sourcing.

The person Meeker listed as the source for the slide, mobile consultant Tomi Ahonen, says he never saw any data to back up the 150 times-a-day number. It was a figure he had heard cited at conferences since 2010. The figures presented in Meeker's bar chart were "definitely only opinion," and "not intended in any way as a 'study' of consumer behavior."

Perhaps more significantly, his blog, in introducing the information, was clearly not discussing smartphones. It read: "What would a 'typical user' do with the non-smartphone today ... ?"

Information defended

Asked about the discrepancies, Meeker's team at Kleiner Perkins argued that the slide was correct overall.

They said data from a key secondary source - Danielle Levitas of International Data Corp. - backed up the information Meeker presented, but that they didn't have rights to use it at the time of the presentation or they would have listed it as a source.

Levitas disagreed. Contacted by The Chronicle, she said her data, which tracked social media use on smartphones, could not be used to back up the 150 times-a-day statistic in any reasonable way. She also said her data had been public since March, so anyone could have used it in a presentation.

Meeker and her team offered other arguments and statistics to support the 150 times-a-day claim and to buttress the use of Ahonen's opinions in the bar chart. But nothing they provided directly supported the number she quoted onstage that was cited so often afterward.

Levels of use

Even if it had been based on solid factual data, the claim of any "average" of cell phone use struck some experts as unlikely at best.

Tye Rattenbury, a data researcher who has studied the frequency of smartphone use at Intel, said he didn't believe there is a single number to represent all users' smartphone use.

"It definitely differs too much to have one group," he said in an e-mail. "In my research, the best breakdown was into levels of usage: light users, medium users and heavy users."

In a rare interview, Meeker discussed how she finds and checks the data she is so famous for disseminating.

"I love data. I think it's very important to get it right, and I think it's good to question it," she said. "We want to start a conversation. We do not see our role as being the sole authority."

But that is the position in which Meeker, with the help of a sometimes credulous tech press, finds herself.

Besides her "queen of the Net" designation, Time has called her one of the most influential women in tech. The smartphone factoid became one of her presentation's biggest takeaways, written about by Mashable, Time, the New York Daily News, ABC News, and many more.

Consider the source

"The important thing here is the context," said Alex Howard, a writer and editor who covered government and tech for years for O'Reilly Media and other outlets. "It's Mary Meeker. This presentation has really been treated as a state of the industry (report)."

As a result, he said, her statistics may go unquestioned. "The race there (for the press at the conference) was to post. And I think it's emblematic of a broader industry trend."

Stanford University lecturer Howard Rheingold, who has written about and taught digital media for decades, said the episode represents "one of the many reasons we need journalists experienced in the craft of fact-checking. ... The media megaphone that some of these spokespeople have at their disposal can turn poorly sourced or even made-up statements of fact into the kind of search-engine-substantiated factoids that Stephen Colbert called 'wikiality.' "

Meeker's team has changed parts of several slides since talking with The Chronicle, including the headline and sourcing of the smartphone use slide.

But it appears that genie may be out of the bottle. References to Meeker and the 150 times-a-day statistic now appear in Google search results more than half a million times.